This invention responds to the need for a better method of inventory reconciliation as related to the convenience store and auto/truck service station industry. An average store will pump in excess of 100,000 gallons per month and at today's prices losses can be considerable in a relatively short period of time. General accounting practices with their inherent time lags are not fast enough to identify these losses when they occur. This invention is designed to constantly reconcile these inventories and through statistical data analysis help uncover a loss before it becomes a problem.
The prior art discloses a means of detecting losses in fuel tanks which are frequently dispensed from, described in U.S. Pat. No. 5,056,017 issued to D. McGarvey on Oct. 8, 1991. The McGarvey system requires a considerable amount of hard wiring between each metering means and each tank level sensing means to a processor. Such an installation for an existing store would be cost prohibitive. The installation of a pulser means and a level sensor means within an area in which Class 1 liquids are dispensed and stored would further preclude the installation of such a system without the use of expensive intrinsically safe devices. The addition of such a pulser means to an already approved metering means would void the metering means listing with the approval authorities.
The accuracy of a modern tank monitor system, such as the Veeder Root Model TMS250 which utilize magnetostrictive technologies, addresses fuel tank inventory considerations not even considered in the acoustical level sensor means described in the McGarvey system. These considerations include tank tilt, fuel temperature coefficients, temperature gradients within the tank and water in the tank. Any of these considerations can render the results obtained through the McGarvey system inconclusive.
The implementation of the McGarvey system would be extremely difficult, if not impossible to implement on a practical scale.